In the Linux kernel, the following vulnerability has been resolved:
netfilter: nfnetlink_log: wait for rcu grace period before freeing pernet state
sashiko reports: "nfnl_log_net_exit() calls nf_log_unset(), which
clears the logger pointer without an RCU grace period. Immediately after,
ops_free_list() frees the per-net state while concurrent packets might
still be executing nf_log_packet() under rcu_read_lock()."
Clear the pointer via .pre_exit to make sure rcu readers have completed
before pernet storage is free'd. The change in nf_log_syslog.c is only
done for consistency: it doesn't use pernet data.
Attack Parameters
Attack Vector
Local
Requires local access
Attack Complexity
Low
Easy to exploit
Privileges Required
Low
Basic privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
High
Complete denial of service
CVSS Vector v3.1
References 3
https://git.kernel.org/stable/c/33d1469b0124cc0baaea7a2032123b77a81e0940
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/dc20050b6b12ca58066715d088e1a537535d938d
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/f4461654374576e9d5d0245fd534c46ad8509051
416baaa9-dc9f-4396-8d5f-8c081fb06d67